CODING AGENT / DEV TOOL · WORTH A LOOK
Sandcastle (Matt Pocock)
Matt Pocock's TypeScript toolkit for running coding agents in isolated sandboxes, one pull request per task.
What Sandcastle (Matt Pocock) does
Open-source TypeScript toolkit by Matt Pocock for orchestrating coding agents in isolated sandboxes with sandcastle.run(): each task gets its own git worktree and sandbox and ends in a pull request. His v1 plan (1 Nov 2026, not shipped yet) pitches it as a 'software factory': six built-in harnesses (Claude Code, Codex and others), sandbox providers such as Daytona, Vercel and E2B, Inngest/Trigger.dev templates, human-in-the-loop over Slack or Discord, and skills as Agent() functions (CodeReview(), ImplementSpec(), Retro()).
Good for
- Run several coding agents on separate tasks safely, each in its own sandbox, and review their pull requests
- Build a repeatable review/implement/retro pipeline for a small dev team
Try this in 10 minutes
Honest take
No red flags in our notes so far
We have not written a detailed take on this tool yet. The summary above is based on the maker’s own website.
Pricing
Free, open source; sandbox providers and model usage billed separately
Prices as listed by the maker when we last checked (2026-11-02); usually in US dollars. Check the website for current prices.
Latest update
- : Added: v1 'software factory' plan announced (harnesses, sandbox providers, human-in-the-loop); plan, not a release.